Rotary offset printing press



July 1, 1969 H. B. BOLZA--SCHUNEMANN ET AL 3,452,672

Ronny OFFSET PRINTING mass Filed Nov. 2. 1966 Sheet of 3 Fig. 1 z

y 1, 1969 H. B. BOLZA--SCHUNEMANN ET AL ,672

' ROTARY OFFSET PRINTING'PRESS v Filed Nov. 2, 1966 y eet 5 of 3 Fig. 2. 21 I Ju1y1,1959 H. s. BOLZA-SCHUNEMANN ETA!- 3,452,672

ROTARY OFFSET PRINTING PRESS Filed Nov. 2, 1966 7 Sheet .3 of 3 Fig.3

United States Patent 3,452,672 ROTARY OFFSET PRINTING PRESS Hans B. Bolza-Schiinemann and Albrecht Germann,

Wurzburg, Germany, assignors to Schuellpressenfabrik Koening & Bauer Aktiengesellschaft, Wurzburg, Germany Filed Nov. 2, 1966, Ser. No. 591,626 Claims priority, application Germany, Nov. 11, 1965, Sch 38,011 Int. Cl. B41f 5/16 US. Cl. 101-177 6 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to improvements in a rotary offset printing press, and it is an object of this invention to provide a mechanism for engaging the associated printing cylinders of such a machine with each other and disengaging them from each other and for changing-over the blanket cylinder of one of two offset units of such a machine from a common impression cylinder to the blanket cylinder of the other offset unit or vice versa so as to permit multicolor recto printing as well as perfecting work to be carried out alternately on the same machine.

More particularly, it is an object of the present invention to provide a very simple and inexpensive mechanism which combines the elements of two separate mechanisms with each other so as to form a single structural unit which is capable of carrying out both of the functions as mentioned above, namely, of engaging and disengaging the associated printing cylinders and also of shifting a blanket cylinder from one position in which it engages with the common impression cylinder to another position in which it engages with another blanket cylinder.

For attaining this object, the invention provides that for engaging and disengaging the associated cylinders or, to say it in other words, for moving them from the impression-on position to the impression-off position or vice versa, these cylinders are mounted on eccentric bushings which are adapted to be turned by means of toggle levers which are bent by suitable means to different angles relative to each other. For the additional purpose of this mechanism of shifting a blanket cylinder of one offset unit from its position for carrying out pure recto printing in which it engages with the common impression cylinder to the position for carrying out perfecting work on this same machine in which this blanket cylinder engages with a blanket cylinder of the other offset unit, the invention provides that the crank arm of the toggle unit of the shiftable blanket cylinder is pivotable to either of two diametrically opposite positions relative to the axis of the crankshaft which rigidly connects this crank arm on one end of the blanket cylinder to the corresponding arm on the other end. In one of these positions, the eccentric bushings of the blanket cylinder will therefore be pivoted so as to engage the latter with the impression cylinder, while in the other position these bushings will be pivoted so as to shift the blanket cylinder into engagement with the other blanket cylinder. The invention further provides an additional coupling device which is rotatably mounted on the mentioned crankshaft and connected to the driving means for operating the toggle unit and adapted to lock the crank arm in either of these positions to the mentioned driving means. Thus, the adjustment of the blanket cylinder to either of these positions may be carried out independently of the actuation of the toggle unit by its driving means, and the blanket cylinder may therefore be moved in either of these positions to its impression-on or ofl? positions, that is, into or out of engagement with the common impression cylinder or with the other blanket cylinder.

This coupling device may be of a very simple and inexpensive construction and the operation of pivoting the crank arm from one position to the diametrically opposite position and thus the movement of the blanket cylinder from one to the other associated cylinder as well as the operation of locking and unlocking the coupling device in either of these positions may be carried out very easily either by hand or by mechanical, hydraulic or electric means. After the shifting operation has been completed and the coupling device has been locked in the new position, the associated cylinders may, if desired, also be shifted to the impression-on or off positions so as to be either in positive engagement with each other or slightly spaced from each other.

The features and advantages of the present invention will now be described in greater detail with referrence to the accompanying diagrammatic drawings, in which:

FIGURE 1 shows a side view of the mechanism according to the invention in which the machine is adjusted for carrying out multicolor recto printing;

FIGURE 2 shows a similar side view of the mechanism in which the machine is adjusted for carrying out perfecting work; while FIGURE 3 shows a cross section which is the line IIIIII of FIGURE 1.

The drawings illustrate diagrammatically a five-cylinder printing mechanism of an offset machine for multicolor printing, which comprises a common impression cylinder 1 for the two blanket cylinders 2 and 3 of two offset units, each of which further comprises a plate cylinder 4, which is adapted to cooperate with the blanket cylinder 3, while the other plate cylinder which is not illustrated is adapted to cooperate with the blanket cylinder 2. All of the cylinders are provided in a conventional manner at least at one end with gear teeth (not shown) so that, when pure recto printing is to be produced and the two blanket cylinders 2 and 3 are in the position as illustrated in FIGURE 1 and in engagement with the common impression cylinder 1 which is driven in the direction as indicated by its arrow, the teeth of cylinder 1 will mesh with the teeth of the two blanket cylinders 2 and 3 and drive the latter in the directions as indicated by their arrows, while the blanket cylinder 3, in turn, will drive the plate cylinder 4. If, on the other hand, perfecting work is to be carried out on this machine in accordance with the principle of blanket-to-blanket, as illustrated in FIGURE 2, and the blanket cylinder 3 is then in the impression-on position in engagement with the other blanket cylinder 2 rather than with the impression cylinder 1, cylinder 2 is again driven by the impression cylinder 1 by the interengaging teeth of both cylinders, and the teeth of the blanket cylinder 2 are in mesh with those of the blanket cylinder 3 which is thereby driven in the opposite direction as indicated by its arrow in FIGURE 2, and the teeth of cylinder 3 are again in mesh with those of the plate cylinder 4. When carrying out perfecting work, the impression cylinder 1 therefore operates merely as a sheet-transfer cylinder without taken along any printing function and it feeds the sheet to the blanket cylinder 2 which picks up the sheet by means of grippers thereon (not shown) and passes it along the other blanket cylinder 3 to the printing position where it will be printed on both sides between the blanket cylinders 2 and 3.

For moving the blanket cylinders 2 and 3 and also the plate cylinders 4 from the impression-off position to the impression-on position or vice versa, each of these cylinders is provided with an eccentric bushing 5 or 6 which, in turn, is rotatably mounted on the shaft of the respective cylinder and adapted to be pivoted from one position to the other into or out of engagement with the associated cylinder by means of toggle-lever units. According to the invention, the same toggle-lever unit which consists of the connecting arm 8 and the crank arm and serves for moving the blanket cylinder 3 from the impressionoff position to the impression-on position or vice versa also serves for shifting this cylinder 3 from its recto-printing position in engagement with the impression cylinder 1 to the perfecting-work position in engagement with the other blanket cylinder 2. This is accomplished according to the invention by providing an additional releasable coupling device 16 which connects the crank arm 10 to the driving means of this toggle-lever unit.

FIGURE 3 illustrates one of the two eccentric bushings 5 which are mounted on the outer ends of the blanket cylinder 3 and each of which has a flange which carries a pin 8 which is spaced at a radial distance 7 from the axis of rotation of bushing 5, as indicated by the dot-anddash line 7'. This flange of bushing 5 has pivotably mounted thereon one end of the connecting arm 8 of the toggle-lever joint, the other end of which is mounted on a crank pin 9 on one side of a crank arm 10 which is pivotable back and forth and rigidly splined on a crankshaft 11 which transmits its movements to the corresponding crank arm 10 on the other side of the machine (not shown). The hub of crank arm 10 is inserted into the bore of a flanged bushing 12 and rigidly connected thereto. This bushing 12 is rotatably mounted in one side wall 27 of the machine and forms one member of a releasable coupling device. The other side of the crank arm 10 with respect to the crankshaft 11 forms a substantially semicircular segmental rack 13 which engages with a pinion 14 which is rotatably mounted on the side wall 27 of the machine and may when the machine is stopped be driven either by hand or by a motor for the purpose of turning the crank arm 10 to either of two diametrically opposite positions relative to the axis of crankshaft 11 and for thereby turning the bushings 5 of the blanket cylinder 3 so as to shift the latter from its position in engagement with one of the two cylinders 1 or 2 to the other.

For moving the blanket cylinder 3 in either of its two positions relative to cylinders 1 and 2 from the impression-on position to the impression-off position or vice versa, that is, either into or out of engagement with the impression cylinder 1 or with the blanket cylinder 2, the crankshaft 11 carries a tubular shaft 15 which is freely rotatable thereon and extends from one side wall 27 of the machine to the other and has a swivel arm 16 rigidly splined on each end thereof. This swivel arm 16 which forms another member of the coupling device and is operatively associated with the flange on bushing 10 has a bifurcated end 16a to which a connecting rod 17 of a suitable driving device is pivotably connected which may consist, for example, of a hydraulic cylinder-and-piston unit 18, as indicated in dashed lines in FIGURES 1 and 2. This swivel arm 16 may be connected in different angular positions to the bushing 12 by means of an axially slidable coupling pin 19 which is for this purpose adapted to be inserted into one or another of two diametrically opposite bores 20 and 22 in the flange of bushing 12 or into an intermediate bore 21 in this flange. Coupling pin 19 may be moved back and forth either by hand or automatically by mechanical, magnetic or hydraulic means. When the blanket cylinder 3 is to be moved from the impression-on position to the impression-off position or vice versa in either of its two positions according to FIGURE 1 or FIGURE 2, the crank arm 10 remains locked by the coupling pin 19 to the swivel arm 16 on the tubular shaft 15.

Each of the swivel arms 16 which are secured to both ends of the tubular shaft 15 also serves as a crank arm for the toggle-lever unit for moving the plate cylinder 4 into or out of contact with the blanket cylinder 3 when the latter is shifted from its impression-on position to its impression-off position either in cooperation with cylinder 1 or cylinder 2. Plate cylinder 4 is likewise slightly retracted in the same manner from the blanket cylinder 1 to theother blanket cylinder 2 or vice versa. The bifurcated end 16a of each swivel arm 16 is for this purpose provided with a crank pin 23 on which one end of a connecting arm 24 is pivotably mounted, the other end of which is connected to the eccentric bushing 6 of plate cylinder 4. Swivel arm 16 is made of such an effective length and the angle of traverse of the eccentric bushing 6 is made of such a size that, although when the plate cylinder 4 is moved to its impression-off position, its teeth will remain in mesh with those of the blanket cylinder 3, the peripheral surfaces of these two cylinders will then be disengaged from each other. The eccentric bushing 6 is located in such a position that, when plate cylinder 4 is moved from its impression-on position to its impression-oft position, its axis of rotation will move substantially within the plane which intersects this axis with that of cylinder 3, so that only a small turn of bushing 6 will be required to effect a sufficient movement of plate cylinder 4 to disengage it from the blanket cylinder 3.

For changing the blanket cylinder 3 from its position for producing pure recto printing to that for perfecting Work or vice versa, it is merely necessary to retract the coupling pin 19 from the bore 20 or 22 in the flange of bushing 12 and to turn the crank arm 10 about an angle of 180 in one or the other direction relative to its driving part, i.e., the swivel arm 16, and then to reinsert the coupling pin 19 into the other bore. When crank arm 10 is thus turned to the position in which the coupling pin 19 is inserted into the bore 20, the blanket cylinder 3 will be in the position for producing pure recto printing, while when crank arm 10 is turned so that the coupling pin 19 is inserted into the diametrically opposite bore 22, cylinder 3 will be in the position for carrying out perfecting work. The intermediate bore 21 is disposed at an angle of relative to bores 20 and 22 and determines a neutral position of blanket cylinder 3 in which it is out of contact with both cylinders 1 and 2. This neutral position of cylinder 3 may be used for insuring that, when this cylinder is shifted from cylinder 1 to cylinder 2 or vice versa, its teeth will properly engage with those of the cylinder to which cylinder 3 is shifted. This neutral position of blanket cylinder 3 may further be used for washing and make ready the different cylinders and for the application of ink. Cylinders 3 and 4 may for any of these purposes be rotated either by hand or by auxiliary driving means.

As previously indicated, the selective adjustment of blanket cylinder 3 from the position according to FIGURE 1 for pure recto printing to the position according to FIGURE 2 for perfecting work or vice versa may be carried out either by hand or by suitable driving means which permit the pinion 14 to be turned only when the coupling pin 19 is retracted. Pinion 14 is then turned so as first to turn the crank arm 10 together with bushing 12 about an angle of 90 until the intermediate bore 21 is in alignment with the coupling pin 19. The rotation of pinion 14 is then stopped and the coupling pin 19 is inserted either by hand or automatically into bore 21 so that the blanket cylinder 3 is locked in its neutral position. If necessary, cylinder 3 may then be slightly turned while its teeth remain in mesh with those of the plate cylinder 4 so that at the end of the subsequent movement of cylinder 3 toward the cylinder 1 or 2, its teeth will properly engage with those of the latter. Coupling pin 19 is then again retracted and blanket cylinder 3 is further moved until it reaches either the other blanket cylinder 2, as shown in FIGURE 2, or the impression cylinder 1, as shown in FIGURE 1. Cylinder 3 is then locked in this position by the insertion of coupling pin 19 either into the bore 20 or the bore 22.

Cylinders 3 and 4 are moved to the impression-off position while the teeth of blanket cylinder 3 remain in mesh with those of the associate cylinders. If imperfectly printed sheets or stoppers occur, cylinders 3 and 4 may be moved to the off-position automatically by means of a photoelectric cell or the like or by hand by the actuation of a pushbutton. In any event, however, the coupling pin 19 then remains in its particular bore 20 or 22 in the flange of bushing 12.

When the blanket cylinder 3 is in its impression-on position either for carrying out pure recto printing or perfecting work, the arms 8 and 10 of one toggle-lever unit and also the arms 16 and 24 of the other toggle-lever unit are in straight alignment with each other so that the longitudinal axes of the arms 8 and 24 are substantially in alignment with or intersect the axis of crankshaft 11. No torque will therefore be exerted upon the toggle units when the cylinders 3 and 4 are in the impression-on position, and the hydraulic unit 18 may remain inactive during the printing operation, while it only needs to overcome frictional forces at the beginning of the movement of cylinders 3 and 4 to the impression-off position. After they have been moved to this position in which the toggle-lever units are in the positions as indicated in FIGURES 1 and 2 in dot-and-dash lines, they will be maintained in this position by the pressure within the hydraulic unit 18.

In order to permit the mechanism to be accurately adjusted, the connecting arm 8 is mounted on the crankpin 9 by means of an intermediate eccentric bushing 26 which may be turned on pin 9 so as to vary the elfective length of the connecting arm 8, while the connecting arm 24 is made of two parts which are connected by a screw connection for also varying its effective length.

Having thus fully disclosed our invention, what we claim is:

1. In a rotary offset printing press for multicolor printing having a common impression cylinder and two offset units each comprising a blanket cylinder and a plate cylinder adapted to engage upon and rotate with one of said blanket cylinders, at least one of said blanket cylinders having at least one eccentric bushing, and common means for pivoting said bushing so as to move at least a first of said blanket cylinders from the impression-on position to the impression-off position and vice versa and also for shifting said first blanket cylinder from a first position opposite to said impression cylinder to a second position opposite to the second blanket cylinder and vice versa, said common means comprising a shaft, rotatable about a fixed axis, a toggle-lever unit having a connecting arm pivotally connected at one end to said bushing and a crank arm secured to said shaft and pivotally connected to the other end of said connecting arm and adapted to be turned with said shaft about said axis to at least two different locking positions for moving said first blanket cylinder to said first and second positions, and a coupling device comprising a coupling member rotatably mounted on said shaft, and coupling means for releasably locking said coupling member to said crank arm in either of said locking positions thereof, and actuating means for pivoting said coupling member about said shaft when said coupling member is locked to said crank arm and for thereby pivoting said bushing so as to move said first blanket cylinder from said impression-on position to said impression-off position and vice versa.

2. A rotary offset printing press as defined in claim 1, in which said two locking positions of said crank arm are substantially diametrically opposite to each other relative to said axis.

3. A rotary offset printing press as defined in claim 1, in which said crank arm on said shaft has a flange thereon, said flange having a pair of substantially diametrically opposite bores forming said two locking positions, and an intermediate bore between said pair of bores forming an additional locking position, said coupling means comprising a coupling pin slidable in its axial direction in said coupling member and adapted to be partly projected therefrom into either of said bores when said crank arm is turned accordingly, said coupling pin when inserted into said intermediate bore maintaining said first blanket cylinder in a neutral position out of engagement with said impression cylinder and said second blanket cylinder.

4. A rotary offset printing press as defined in claim 3, in which said crank arm forms a segmental rack, and a pinion engaging with said rack and adapted to be rotated for rotating said crank arm from one of said locking positions to the other.

5. A rotary offset printing press as defined in claim 1, in which said plate cylinder which is adapted to engage with said first blanket cylinder also has an eccentric bushing, and a second toggle-lever unit for pivoting said last eccentric bushing so as to move said plate cylinder to its impression-on and otf position into and out of engagement with said first blanket cylinder and comprising a connecting arm pivotably connected at one end to said last eccentric bushing, and a crank arm pivotably connected to the other end of said connecting arm, said coupling member also forming said last crank arm, said actuating means being adapted to move said first blanket cylinder and said plate cylinder substantially simultaneously to their respective impression-on and off positions.

6. A rotary offset printing press as defined in claim 5, in which said eccentric bushings of said first blanket cylinder and said plate cylinder are adapted to be pivoted by said toggle-lever units to such impression-off positions that, when said first blanket cylinder has been shifted from said first position to said second position opposite to said impression cylinder and said second blanket cylinder and vice versa, it is in its impression-01f position relative to both of said impression and first blanket cylinders and in both first and second positions equally spaced from said plate cylinder in its impression-01f position.

References Cited UNITED STATES PATENTS 952,218 3/1910 Scott 101-137 1,108,223 8/1914 Payne 101-137 3,384,011 5/ 1968 BolZa-Schiinemann 101-137 FOREIGN PATENTS 224,843 11/1924- Great Britain.

ROBERT E. PULFREY, Primary Examiner.

J. R. FISHER, Assistant Examiner.

US. Cl. X.R. 101-229 

